Vacaville Tree Foundation Newsletter

February 2000

This issue:
City open space lands: cow pastures or oak woodlands?

New web site launched
Fall plantings completed

1999 a bad year for varmints

City open space lands: cow pastures or oak woodlands?

With a relatively good local acorn crop this year, the Vacaville Tree Foundation (VTF) faced a potential shortage of city-owned open space land available for planting. "Hundreds of acres of city-owned open space are in dire need of restoration to reduce landsliding and erosion", explains Ted Swiecki, VTF's co-chair, "but we can't simply plant areas that are used for cattle grazing because cattle are death to young oak seedlings."

A controlled study conducted for the California Department of Forestry and Fire Protection on the Hidden Valley Open Space in Vacaville demonstrated that planted valley oak seedlings left unprotected from grazing cattle were all killed in a period of a few years. Over the same period, about 80 percent of the seedlings that were protected by sturdy wire cages survived. Some of the oaks from that 1989 planting are now more than 15 feet tall.

Although the VTF has used protective "Vaca" cages to establish native oaks on grazed land, the technique is relatively expensive and time consuming. A handful of volunteers check and repair over 400 caged planting sites on an annual basis. In the ten years that the cages have been in use, only a few trees have grown large enough that the cages can be removed without risking serious tree damage from cattle browsing. Since 1994, VTF has conducted its annual plantings on non-grazed open space lands. "We can plant hundreds of sites in a single day with even a small a group of volunteers when we are working on nongrazed land. That means that we can get trees planted over much larger areas," according to Swiecki. Furthermore, planting in nongrazed areas can be done by volunteers free of cost - acorns are gathered from local trees and wood chip mulch is donated. In contrast, each Vaca cage requires over $10 worth of material. "This is a perfect example of doing more with less," Swiecki said.

VTF has been working for years to get the city to change its grazing practices on open space lands with relatively little success. If city grazing practices don't change, the oaks currently growing on the publicly-owned hills will likely be the last generation. On grazed hillsides, trees that die are not being replaced by new seedlings. Natural reproduction is eliminated by excessive grazing and planting large areas using Vaca cages would be prohibitively expensive. "Besides," Swiecki notes, "cages can only protect individual trees. Many other native plants and wildflowers are also wiped out by grazing, and individual cages can't protect all these other elements of the oak woodland." Furthermore, current grazing practices have favored the buildup of noxious weeds, including yellow and purple starthistle. These spiny plants are not eaten by cattle and their populations increase as cows preferentially eat other plants that would compete with the thistles.

City officials consistently cite fire protection as the main reason for grazing open space areas. Swiecki counters that dry starthistle is every bit as flammable as dry grass. In fact, he notes that dry starthistle is actually a greater fire hazard late in the season than annual grasses because it remains upright rather than laying down as the annual grasses typically do. Consequently, current grazing practices, especially on large open spaces such as the Old Rocky ridge and the Araquipa Hills around Lagoon Valley, do little to reduce fire risk. Heavy tree canopy can suppress the growth of annual plants in the understory to the point that ground fire hazard is greatly reduced. "By suppressing the development of the tree canopy, grazing perpetuates a higher fire hazard," according to Swiecki.

At the same time, current grazing practices increase soil erosion, landsliding, and stormwater runoff, all of which have real costs to the city. Reestablishing native trees on the formerly wooded hillsides would stabilize the soil, reduce erosion and nutrient loss, reduce and moderate winter stormwater runoff and associated flooding, help improve air quality, provide habitat for wildlife, reduce populations of starthistle and other noxious weeds, and help protect remnant populations of native plant species. "It's unfortunate that the city has been so reluctant to improve its management of the open space lands, because the potential benefits provided by better management far outweigh the minimal costs that would be incurred."

A window of opportunity to change city grazing policies may be opening. The multi-year cattle lease for the Araquipa Hills above Lagoon Valley Park ends after this current grazing season. "A change is more likely to occur if city council members and Parks Superintendent Rollie Simons hear from residents who oppose the excessive and counter-productive grazing practices that have been followed," says Swiecki. Removing cattle from city open space lands is only a first step toward the restoration of Vacaville's natural heritage, but it is a necessary prerequisite. "Once the cattle are gone, we can really start to do some serious restoration, but natural processes can also start working. It will be a long, slow process, but the most important step is starting." And that means that it's time to move those dogies along.

New web site launched

If you're reading this you probably aware of VTF's new website. The website ( provides an easier (and cheaper) way to keep VTF faithful and the community at large informed about news, events, and issues that are related to VTF and local natural resources. Like all of VTF's activities, website maintenance is completely supported by VTF volunteers. If you are interested in helping out, contact webmaster Ted Swiecki. Also, zip us an email if you would like to be added to VTF's emailing list (notices about plantings or other projects).

Be sure to bookmark the site and check back from time to time (there's no telling when we might post something new). Also, be sure to pass the website address along to friends, acquaintances, total strangers - anyone who has an interest in Vacaville's trees and other natural resources.

Fall plantings completed

VTF volunteers completed two oak plantings in Vacaville in December 1999. Although we had started to get a bit nervous about the lack of rain, thankfully we have had enough to ensure good germination. Although valley oaks can emerge as early as mid to late March in this area, the lack of early rain may slow shoot emergence. Look for seedlings to be coming up in April and May.

Southside pedestrian / bikeway project

On the morning of December 4, an efficient crew of volunteers came out to plant the Southside pedestrian / bikeway project. We planted 94 sites with valley oak in less than two hours, on the west side of the unpaved section of the bikepath between Marshall Road and Hume Way (the street Meeks is on). The bikepath is due to be paved later this spring or summer. If all goes well, we will complete the project by planting on the east side of the trail in fall 2000, after construction is completed. City crews have installed rebar pins at each of the planting sites to mark the sites and protect the seedlings from errant mowers and herbicide applicators.

Thanks to all those volunteers that participated (and our apologies if we misspelled any names): Paul Adrian, Deborah Bentsen, Liz Bernhardt, Bill Cox, Kelley Cox, Mary De Jong, Rick Duncan, Christina Heckman, Kurt Heckman, Jerry Hill, Andy Johnston, Ernest Kimme, Ruth Kaiser, Gail Korenaga, James Lara, Nick Lorusso, Lewis Martin, Sannie Osborn, Rhett Richardson, Ken Schofield, John Salerno-White, Frances Swiecki-Bernhardt, Ted Swiecki, Derek Tietze, Kimberly Tietze, Richard Tietze, Rachel Tietze, and Robert Zodnik. Special thanks to Solano Shade for providing wood chip mulch, tools, and the use of their truck. Thanks also to United Rentals of Vacaville, who donated the use of the megaphone, and to Utility Tree Service and PG&E who also provided a load of wood chip mulch.

Oak planting in Lagoon Valley

On December 11, 25 volunteers came out on a salubrious fall morning and planted about 230 sites with valley oak, California buckeye, and a few blue oaks in three hours. Our planting site was about 5 acres in the nongrazed area above the bladed trail used by the cross-country teams on the east side of the lake. Special thanks again to Solano Shade for providing wood chip mulch. Thanks also to all the volunteers that came out: Liz Bernhardt, Kay Brochhauser, Jim Clark, Mark Dodini, Bill Dolter, Jean Dolter, Rick Duncan, Peaslee DuMont, Cindy Gilpin, John Gilpin, Earl Heal, Jerry Hill, Andy Johnston, Ernest Kimme, Gail Korenaga, Pam Muick, Jesse Muick-Amme, Emily Rued, Ted Swiecki, Frances Swiecki-Bernhardt, Derek Tietze, Kimberly Tietze, Richard Tietze, Rachel Tietze, and Brooke Wolfe.

1999 a bad year for varmints

Astute observers may have noticed a number of young oak seedlings that turned brown a bit early this past year. In most cases, the reason was that voles had girdled the seedlings by chewing through the bark at the base of the seedling. Vole populations were apparently high as a result of the last El Nino - wet winter weather increases the amount of annual grasses, the seeds of which are a primary food source for voles. With relatively few predators such as foxes, coyotes, hawks, and owls to help keep the population in check, vole populations apparently boomed and many hungry voles developed a liking for the bark of young oaks. One of the most disheartening sights we observed was a valley oak sapling at least 3 inches in diameter at the base which was completely girdled.

As revolting as this development is, all is not lost even for oaks that were topkilled through girdling. Almost all healthy oak seedlings and saplings will resprout vigorously from the base if the top is killed by cutting, fire, or girdling. This resprouting process can be repeated a number of times, as long at the root system has sufficient energy reserves. If the vole populations decrease to more normal levels, many of the oaks will come back, although they have certainly lost some ground. Setbacks such as this are one of the reasons that restoring oak woodlands is a long-term project.